Recently, research and development have been actively performed on a wavelength-tunable lasers the oscillation wavelength of which is tunable since application to various fields such as communication, sensing, imaging, and so forth can be expected. As a wavelength-tunable laser, a configuration in which one of a pair of reflectors of a vertical cavity surface emitting laser (hereinafter referred to as VCSEL) is moved, has been developed. Specifically, by mechanically moving one of a pair of reflectors (a movable reflector) by micro electro mechanical systems (hereinafter referred to as MEMS) technology, the resonator length is fluctuated, and the oscillation wavelength of the VCSEL is changed. Such a VCSEL will hereinafter be referred to as a MEMS-VCSEL.
As a movable reflector, a distributed Bragg reflector (hereinafter referred to as DBR) made of dielectric can be used. NPL 1 discloses a MEMS-VCSEL in which a dielectric DBR is formed on the top of a beam portion, and wavelength is tuned by driving the beam portion.